The victims tried to escape their homes impacted by mudflows and flooding but they got trapped in cars and buildings, the Los Angeles Times reported citing the Santa Barbara County Fire Department.
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Local authorities launched rescue operations and ordered temporary road closures in the areas of Santa Barbara, Ventura and Los Angeles counties.
The authorities have also advised residents to stay off roads or go on higher ground.
Emergency crews continue to work in the affected areas, but detailed information on killed and injured persons has so far not been made available.